1. Field of the Invention
This invention relates to an operator's compartment that is supported for independent up and down movement on the side wall of a self propelled mine vehicle, and more particularly to an operator's compartment arranged to move upwardly and downwardly independent of the up and down movement of the vehicle as the mine vehicle moves over the uneven surface of the mine floor.
2. Description of the Prior Art
Self propelled mine vehicles, such as shuttle cars and continuous mining machines are used in mines for mining and transporting dislodged material from a mine face. A typical shuttle car includes a longitudinally extending compartment in which the mined material is loaded and after loading, the shuttle car moves from an area adjacent the mine face to a fixed haulage system where the coal is discharged from the shuttle car onto a conveyor belt.
The mine vehicles are controlled from an operator's compartment that is secured either rigidly or floatingly to the side wall of the vehicle body. Suitable controlls are provided on the operator's compartment by which the operator controls the movement of the vehicle between the mine face and the discharge point and operates the conveyor of the haulage compartment.
The machine operator in the operator's compartment is exposed to the mine roof and is, therefore, subject to serious injury from falling debris. Mine safety requirements now require that the machine operator be protected from overhead debris falling from the roof. Thus it has become the practice to utilize overhead canopies for protecting operator's of various equipment in the mine from the hazards of roof falls. For some shuttle cars and mining machines, however, the limited overhead clearance of the operator's compartment hinders the installation of the canopy particularly when the vehicle is operated in a mine having a height of less than 48 inches. With the operator's compartment fixed on the vehicle and raised on the mine floor by the necessary ground clearance between the bottom of the compartment in the mine roof, there is insufficient clearance above the top of the shuttle car for installation of an overhead protective canopy. Furthermore, when there is little clearance between the top of the canopy and the mine roof, the canopy will strike the mine roof as the shuttle car moves upwardly and downwardly as it travels over the undulating surface of the mine floor.
U.S. Pat. Nos. 4,078,629 and 4,157,878 disclose operator's compartments which float relative to the body of a shuttle car vehicle. These compartments are mounted on the shuttle car vehicle body for vertical movement with respect thereto by rails mounted on the compartment which engage guides mounted on the vehicle body. It has been found that under actual operations the rails of the designs of these patents have a tendency to bind in the guides when the operator's compartment is cocked as when only one end engages an undulation in the mine floor as the shuttle car traverses the mine. This engagement with an undulation tends to rotate the operator's compartment by lifting the end thereof which is engaging the undulation while no equal force is lifting the opposite end of the compartment with the end result causing a binding in the tracks of U.S. Pat. Nos. 4,078,629 and 4,157,878.
An additional U.S. Pat. No. 4,146,106 discloses an operator's compartment which can be either free floating or be raised to be above the level of the undulations on the mine floor. Again this design utilizes rollers and rails to interface between the free floating operator's compartment and the vehicle body. Like the patents discussed above if the forward end of the operator's compartment encounters a large undulation in the mine floor the entire compartment can be cocked thereby inhibiting the free floating action of the compartment.
U.S. Pat. No. 2,970,664 discloses a suspension system for a shuttle car utilizing a chain and cylinder arrangement.
While it is suggested in the prior art to have a free floating operator's compartment nowhere is there a means suggested for transferring a portion of vertical forces devloped between the mine floor and one end of an operator's compartment to the other end of the operator's compartment so that cocking of the operator's compartment is eliminated and the compartment floats levelly in the vertical direction with respect to the vehicle body as the vehicle travels over the undulating surface of the mine floor.